Jeremy Corbyn attacked Sports Direct boss Mike Ashley over what he claimed were “grotesque levels of danger and exploitation” at the firm’s headquarters, in his speech at the Durham Miners’ Gala.

Singling out Mike Ashley, Mr Corbyn said that at his firm’s main Sports Direct warehouse there were “people not even getting the minimum wage, hundreds on zero hours contracts and grotesque levels of danger and exploitation”.

During a grilling in front of a parliamentary select committee last month, Mike Ashley admitted to paying some staff less than the minimum wage.

The inquiry also heard damning evidence from representatives of trade union Unite, who painted a picture of staff in a constant state of fear who felt unable to take a day off work when they were ill - or even when about to give birth.

Mr Ashley said he was personally leading an investigation into the claims and told MPs his business was refunding any pay owed - adding that he would personally check that the payments were made.

Mr Corbyn also used his speech at the 132nd annual Durham Miners’ Gala to shrug off the suggestion that he was under pressure, despite a leadership challenge being announced while he was at the event.

Mr Corbyn, the headline speaker at the biggest annual celebration of trade unionism in the UK, said: “There is no pressure on me, none whatsoever.

“Real pressure - real pressure - is when you don’t have enough money to feed your kids, when you don’t have a roof over your head, when you are wondering if you are going to be cared for, when you are wondering how you can survive, you are wondering how you are going to cope with the debts you have incurred, you are wondering if your lovely employer is going to give you a call to give you a couple of hours work or not bother, or change their mind when you are on the bus on the way to do that job.